1 files changed, 3 insertions, 2 deletions
diff --git a/nixpkgs/pkgs/development/compilers/gambit/gambit-support.nix b/nixpkgs/pkgs/development/compilers/gambit/gambit-support.nix
index f78c99a50700..6e42b9252f24 100644
--- a/nixpkgs/pkgs/development/compilers/gambit/gambit-support.nix
+++ b/nixpkgs/pkgs/development/compilers/gambit/gambit-support.nix
@@ -16,12 +16,13 @@ rec {
         --replace "echo > stamp.h;" "(echo '#define ___STAMP_VERSION \"${git-version}\"'; echo '#define ___STAMP_YMD ${toString stampYmd}'; echo '#define ___STAMP_HMS ${toString stampHms}';) > stamp.h;";
     '';
     modules = true;
-    extraOptions = [];
+    #extraOptions = [];
+    extraOptions = ["--enable-trust-c-tco" "CFLAGS=-foptimize-sibling-calls"];
   };
 
   unstable-params = stable-params // {
     stable = false;
-    extraOptions = ["--enable-trust-c-tco"];
+    extraOptions = ["--enable-trust-c-tco"]; # "CFLAGS=-foptimize-sibling-calls" not necessary in latest unstable
   };
 
   export-gambopt = params : "export GAMBOPT=${params.buildRuntimeOptions} ;";